The invention relates to a transfer press having gripper rail parts that can be moved in a lifting and lowering direction and comprises first gripper rail parts located in the press and exchangeable gripper rail parts located on sliding tables that can be moved into and out of the press for engagement between the first gripper rail parts. A coupling mechanism is provided for joining these gripper rail parts by pressing flange facings located in an end of one of these gripper rail parts against flange facings in the end of another adjacent gripper rail part to be coupled to the first gripper rail part.
The exchange of gripping tools and of the exchangeable adjacent gripper rails carrying these gripping tools, takes place during tool changes by means of sliding tables which can be moved into the press and out of it. The exchangeable gripper rail parts can be disconnected from the first gripper rail parts remaining in the press and can be connected to them.
In DE 35 01 946 C2, a connecting arrangement was described comprising connecting devices which form-fittingly cooperate with one another in the connected position. The front faces of the gripper rail parts have surfaces which, in the connected position are pressed against one another by means of a rotary tightening device. The surfaces are complimentary interfilting cone-shaped areas. The rotary tightening device is inserted in an end part of a gripper rail part and has a tension rod which is rotatable and can be moved in an axial direction. The tension rod can be moved out of the end part of one of the gripper rail parts and into the end part of another gripper rail part that is to be connected, and after being turned and pulled back, by the application of force, a T-shaped end of the tension rod is fixed behind a clamping surface to hold the two gripper rail sections together.
The moving of the exchangeable gripper rail part out of the press and the moving of the exchangeable gripper rail part into the press requires a separating gap between the front faces of the gripper rail parts that are to be connected with one another. The separating gap is to be produced by means of the movement of the tension rod during the disconnecting operation, by a pushing-apart of the gripper rail parts, and, during the connecting, the separating gap is closed by means of the pulling-together of the gripper rail parts.
The arrangement according to DE 35 20 343 A1 is also based on the requirement of a separating gap. This separating gap is bridged by wedges which are moved into the clearance between the ends of the gripper rail parts, during the connecting process by means of a tension rod of a rotary tightening device before the tension rod is fixed behind a clamping surface by turning and pulling-back.
It is the object of the invention to permit a connecting and disconnecting of gripper rail parts which does not require any separating gap. In a transfer press having gripper rail parts that can be moved in a lifting and lowering direction and which comprises first gripper rail parts located in the press and exchangeable gripper rail parts, located on sliding tables that can be moved into and out of the press for engagement between the first gripper rail parts, a coupling mechanism is provided for joining these gripper rail parts by pressing flange facings located in an end of one of these gripper rail parts against flange facings in the end of another adjacent gripper rail part, to be coupled to the first gripper rail part. Here a non-separating gap is obtain by having flange facings that have a flat plane surface parallel to the lifting and lowering movement of the gripper rail parts and wherein each end face of the gripper rail part has a plurality of flange facings that are complimentary to an adjoining set on an end face of an adjacent gripper rail part, and wherein the flange facings on the engageable gripper rail sections are moved at right angles to their flat surfaces at a separation plane between the two gripper rails during any of lifting and lowering of the rails, or sliding movement of the sliding table into and out of the press.
It is also advantageous to have the flange facings extend over a width of the gripper rail parts and with a width thereof being less than the movement distance of the sliding table.
Additionally, the flange facings in each set can project different distances from the end faces of the gripper rail parts, in a stair step manner, with the flange facing closest to the press extending out the furtherest, or alternatively all the flange facings can project out at an equal distance without a stair step arrangement.
A center flange facing should have an interruption along its length to allow for passage of a T-shaped hammer head, which extends from one gripper rail part into another and then is rotated to cause the legs of the "T" to engage on a cam surface to force the two gripper rails together. Additionally, the actuator for the T-head can position centering pins between two coupled gripper rail parts as well as move a power coupling device so as to provide a power transfer path between gripper rail parts.
The distance between flange facings should be greater than the width of a flange facing. The ends of the flange facings can be provided with sloped surfaces adjacent their flat plane surfaces.
The development of the front faces at the end parts of the gripper rail parts according to the invention, reduces the exchange time of the gripper rail parts considerably. The machining of the front faces is simplified and therefore less expensive. The number of movements and components for the connecting and disconnecting is reduced. No separating movement and therefore no moving of the gripper rail parts along their length is required. The control of the locking devices at the press and at the sliding table may be simplified. The flange facings, with respect to their flat surfaces, may be enlarged significantly so that surface pressure may be reduced. In individual cases, the lifting and lowering motion for the movement of the flange facings in the connecting and disconnecting plane may be less than the height and possibly the width of the gripper rail parts. The connecting and disconnecting motion of the exchangeable gripper rail part may take place by means of the movement of the sliding table.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.